The present invention relates to a radioactive seed handling device for manipulating radioactive seeds and to a system using the device to load the seeds into an implant or needle for delivery of radiation in or around cancerous growths.
As a result of the continued widespread application of so-called xe2x80x9cseedsxe2x80x9d, i.e. small pellets of low level radioactive material, to deliver localized radiation in the treatment of cancerous growths, a number of systems for handling the seeds have been developed. For example, U.S. Pat. No. 6,113,529 (xe2x80x9cthe ""529 patentxe2x80x9d) discloses a radioactive seed handling station. Because the seeds are typically inserted in the body via an implant, such as a needle, one critical component of any seed handling system is the mechanism in which the seeds, either alone or in conjunction with non-radioactive spacers, are placed into the needle or other carrier.
Vacuum powered suction is one commonly used mechanism. For example, the ""529 patent discloses a vacuum powered seed handling wand that includes a stop for keeping the seeds within a sterile portion of the wand. In one embodiment, the stop is a material such as mesh and fibers. Placing and using such a material in the wand can be problematic and increases the manufacturing time and expense. In another embodiment, the stop is a narrowed portion the lumen of the wand. Although such a mechanism is effective in limiting the movement of the seeds within the wand, the abutment of a seed against the narrowed portion eliminates or reduces airflow, thereby preventing subsequent seeds from being drawn into the wand.
Thus, a need exists for an improved radioactive seed handling device.
The present invention relates to a radioactive seed handling device for handling a number of radioactive seeds. The device a first tubular section having a first lumen with a first diameter larger than the seed diameter for receiving the seed and a second tubular section coupled to the first tubular section and having a second lumen with a second diameter smaller than the seed diameter for preventing seeds from entering the second lumen. An overlapping portion of the second tubular section is located within the first lumen of the first tubular section and has a vent that allows fluid flow into the second lumen when a seed is obstructing a distal end of the second tubular section.
In one embodiment, the vent is a slit formed on the distal end of the second tubular section. In another embodiment, the distal end of the second tubular section is beveled and the vent is formed by a space created by the beveled end. In another embodiment, the vent is a notch formed in the second tubular section at a distance from the distal end of the second tubular section.
The first tubular section can be made of a material that allows visualization of seeds locating in the first lumen. One such material is glass. The glass can be treated with a shatter resistant protective coating.
In an exemplary embodiment, the first tubular section has a beveled tip. The distal portion of the second tubular section is angled with respect to a proximal portion of the second tubular section and the angle is between about 125 and 145 degrees. In order to provide a fluid-tight seal between the first and second tubular sections, the device can include a connecting tube located between the first and second tubular sections. An example of such a connecting tube is a shrink tube that contracts when heated.
The prevent invention also relates to a radioactive seed handling system. The system includes the radioactive handling device, a vacuum source for generating a vacuum, and a conduit connecting the radioactive seed handling device to the vacuum source. The conduit can include a wand having a handle and a bypass for controlling the vacuum.